What is defined as balanced draft in a combustion system?

Balanced draft in a combustion system refers to a condition where the furnace pressure is maintained at a constant level that is slightly below atmospheric pressure. This slight negative pressure helps ensure that combustion gases are effectively drawn out of the combustion area and that air is properly introduced for combustion. By maintaining this balance, the system operates efficiently, promoting optimal airflow and minimizing the risk of backdrafts or smoke infiltration into the combustion chamber.

This condition is essential for effective burner operation and helps maintain stable combustion conditions, improving overall efficiency and reducing emissions. In contrast to other conditions that may describe pressures or drafts in a furnace, having a constant furnace pressure slightly below atmospheric ensures that the system is functioning optimally, helping to prevent issues related to combustion instability.